Gas testing device



Nov. 21, 1939. F. w. DWYER 2.181,013

GAS TESTING DEVICE Filed April 6, 1938 4 Sheets-Sheet 2 llllllllllllllllll F. W. DWYER GAS TESTINGDEVICE Nov. 21. 1939.

4 Sheets-Sheet Filed April 6, 1938 lllllllllllllllllli Ill! 55 Nov. 21, 1939.-

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F. w. DWYE R GAS TESTING DEVICE 4 Sheets-Sheet 4 w r 115 W Filed April 6, 193 8 Patented Nov. 21, 1939 UNITED STATES an on tartar 17 Claims.

This invention relates to gas testing devices and more particularly to an apparatus for testing the proportionate amount of carbon dioxide gas contained in furnace gases and the like.

One of the objects of the invention is the provision of a new and improved gas tester that is so constructed that tests may be made without moving the device itself during the testing operation.

Another object of the invention is the provision of a new and improved gas testing device that is provided with novel means for causing an intermingling of the gas and testing chemical whereby the tests may be made in a minimum of time.

A further object of the invention is the provision of a new and improved device for determining the proportionate amount of carbon-dioxide gas in various gases that is provided with manually operated means whereby the device may be rendered safe for transportation or readily changed to gas testing condition in a few seconds of time. p

A still further object of the invention is the provision of a new and improved gas. testing device that is simple in construction, composed of a minimum number of parts, that is efiicient and accurate in operation, light in weight, portable, and that is not likely to become deranged, broken or get out of order.

Other and further objects and advantages of the invention will appear from the following description taken in connection with the accompanying drawings, in which:

Fig. l is a perspective view of the device;

Fig. 2 is a transverse vertical section thereof;

Fig. 3 is a section of the gas mixing chamber taken at right angles to that shown in Fig. 2 and showing the gauge element partly in section, and with parts broken away;

Fig. 4 is a side elevation, with parts in section, of a modified form of construction, showing the valve and plunger in lowered positions;

Fig. 5 is a similar view but showing the valve and plunger in elevated positions, with parts in section and parts broken away;

Fig. 6 is a section on the line 6-6 of Fig. 5;

Fig. 7 is a side elevation of a further modified form of construction, with parts in section and parts broken away;

Fig. 8 is a section on the line 88 of Fig. 7 showing the valve and plunger in lowered positions;

Fig. 9 is a similar view but showing the valve and plunger in elevated positions; and

Fig. 10 is a section on the line Ill-40 of Fig, 7.

It is common practice in the construction of gas testing devices to so design the same that it is necessary, during the operation thereof, toinvert "or tilt the device, or at least that portion "5 of it containing the reacting liquid. The present invention seeks to simplify such construction by the provision of an apparatus provided with a liquid reagent reservoir and having a light weight, easily operated element having an extended sur- 1Q face for effecting the necessary intermingling of the gas and liquid to effect the proper reaction and that is easily manipulated by the operator without moving the testing device of the liquid reservoir. '1

, Referring now to the drawings, the reference character I (3 designates the gas testing device which comprises a base H on which is mounted a gauge device l3 and a receptacle l2 for containing the reaction composition. The base ll is provided with flanges 20, Fig. 2, forming feet having apertures 39 for receiving bolts or screws for attachment to a table or other support, if desired.

The receptacle i2 is provided with a base having a flange M which is adapted 'to be secured to the base H as by means of suitable bolts l5. This receptacle is provided with a chamber 6 for containing a liquid capable of reacting onv CO2 gas such as a caustic solution on which floats a layer of neutral liquid such as oil. The upper portion I! of the chamber may be restricted and has its sides parallel as shown moreclea'rly in Fig. 3 of the drawings.

The base It has an enlargement as at I8 which is provided with a threaded opening 99, Fig. 3, adapted to be closed by a plug 2|. The threaded opening 19 afiords a passage for draining or removing the liquid from the chamber I6, when so desired.

The side wall of the upper portion of the receptacle is provided with an enlargement at 22 which has a downwardly and inwardly extending. opening 23 threaded at its upper end and a. plug 24 is adapted to engage therein for closing the 5 opening. The opening permits the introduction of the desired liquids into the chamber l6.

Mounted to reciprocate within the chamber l6 is'a plunger 25 whose cross-sectional area is but slightly less than the cross-sectional area of the 5,0

restricted portion I? of the chamber l6 so that when it is elevated, the gas above it will be forced through and not around it. This plunger may be of any suitable material forming a por ous mass or a mass having interstices therein,

that is, a mass having a large exposed surface. Preferably, the plunger is of alkali-proof reticulated material. In the form shown, the plunger is of wire cloth of fine mesh or of other material not seriously affected by the caustic solution used in the device, such as iron or the like. This cloth may form a cylinder filled with fibrous material such. as steel wool or the like. This plunger is adapted to be lowered into the enlarged portion of the chamber below the layer of oil 9 and raised into the restricted portion thereof above said oil by any suitable means such as the rod 26 which extends through an opening in the head or cap 21 of the receptacle and is rigidly attached to the upper end of the plunger 25 as at 28. The

upper end of the rod 26 may be provided with a knurled handle 29 for raising and lowering the plunger 25.

The upper end of the receptacle is provided with an outwardly extending flange 3! which extends about the same. A head or cap 2'! is secured to the flange 3i as by means of bolts 32, Fig. 3. A suitable gasket 33 is mounted between the cap 21 and the flange 3! 50 as to form an air-tight joint. The cap 21 is provided on its lower surface with a depending portion 34 which is adapted to enter the upper end of the reduced portion of the chamber H for positioning the head or cap 2i thereon.

Suitable passages are provided for conducting the gas to be tested to and from the chamber l6 and also for placing the chamber It in communication with the gauge iii-as will now be described. A tapered opening 35, Fig. 2, extends horizontally through the head 2'! and has its enlarged end screw threaded as at 35 for receiving an internally threaded cap 3'! as shown in Fig. 2. A tapered valve member 33 is mounted in the opening 35 and a spring 59, seating in the cap 31 and in a recess in the outer end of the valve 38, resiliently forces the valve outwardly so as to always insure a tight joint.

The head 21 is provided with a pair of vertically extending bores M and M which extend downwardly through the opening 35 in the central vertical plane thereof. The bores 4E! and 4| extend vertically through the head into the chamber It. The head 21 is also provided with a threaded passage 42, Fig. 3, which extends horizontally from the bore 35 to the exterior of the head.

The valve 38 is provided with a bore 43, Fig. 2, which is adapted to be aligned with the bore M and with a bore 44 which is adapted to be brought into alignment with the bore 40 when the bores M and 43 are in alignment. The valve 38 is also provided with a passage d5, Fig. 3, which extends from the circumference of the valve inwardly and intercepts the bore -14. The passage G is adapted to be brought into register with the threaded opening E2 or with the bore 40, as will presently appear.

The threaded opening 412 is provided with an apertured connector plug 45 to which a connector pipe l! is attached. A flexible tube 50 is adapted-to be attached to the outer end of the connector member 41 and has its free end provided with a connector tube 58 and which is adapted to be attached to the gauge, as will presently appear.

' The bore M is counterbored at its upper end and threaded for receiving an apertured plug or connector member 48 to which a connector tube 49 is attached, as shown in Fig. 2. Attached to the tube 49 is a flexible tube 5i through which the gas is conveyed to the chamber I6. when the same is to be tested. The valve 38 is adapted to be turned to the position shown in Fig. 2 to convey gas to be tested into the chamber 56 and for conveying the same into the atmosphere through the passage 40 and may also be turned into position at right angles thereto as shown by dotted lines in Fig. 3 in which the outer end of the bores All and M will be closed and the bores 40, 44, 45 will place the chamber IS in communication with the gauge 13 through the flexible tube 50, as shown in Fig. 3 of the drawings. The valve 38 may also be turned to an intermediate position where the lower portions of the bores 40 and 4| will be closed.

Any suitable means may be provided for turning the valve. In the form of the construction shown, the outer end of the valve 38 is squared and a handle 52 having an angular socket 53 therein may be provided for engaging the squared shank 54 of the valve, see Fig. 2.

A gauge I3 is also mounted on the base H in proximity to the receptacle l2 and is held in position thereon by a plate 55, Fig. 3, having a flange 56 which is rigidly secured to the flange 3| of the receptacle I2 as clearly shown in Fig. 3 of the drawings. The outer end of the plate 55 is clamped to the upper end of the gauge by a nut 51 on the nipple 5B. The nipple 58 extends through the plate 55 and is threaded into a plug 59 which in turn is threaded into the upper end of the gauge I3.

The gauge l3 comprises a block of suitable transparent material, various types of which are on the market. This block is provided with a uniform bore 6! extending vertically and in alignment with the aperture in the plug 59. The bore 6| extends to the lower portion of the block and then extends laterally outwardly and then upwardly as at 62 to form a U-tube which is adapted to contain a liquid 63 for indicating the pressure. The liquid 63 is adapted to extend upwardly in the bores 6| and (52. The bore 62 is of considerably larger diameter than the bore fi! so that a minimum movement of the level of the liquid in the bore 62 will result in a comparatively large movement of the liquid in the smaller bore 6|. The liquid may be of any suitable material, such as mercury, having a small amount of colored liquid above the same for indicating its height or it may be of some suitable colored liquid.

The upper end of the bore 82 is provided with an apertured plug 64 which is adapted to be closed by a cap 65 for closing the upper end of the tube 62 when the device is not in use. In constructing the gauge, the bore 62 is drilled from above, the connecting portion of the two legs is drilled from the side and the outer end of the bore closed as by means of a plug 55 as shown in Fig.- 3. The bore 5!, of course, is drilled from above and is counter-bored to receive the plug 59. The connector 60 is adapted to be attached to the plug 59 by pushing the same downwardly therein as shown in Fig. 3.

Calibrations are provided on the inner face of a plate 6'! secured tothe block and may be read through the gauge block as indicated in Fig. 3. The plate is provided with a lateral flange 69, Fig. 1, having an elongated opening H therein through which the set screw l2 extends into the gauge block. The slot H permits the calibrated plate to be raised or lowered so as to properly adjust the same to the zero mark before taking the reading.

The larger portion of the chamber I6 is filled with a caustic solution 8 such as potassium or sodium hydroxide and a layer of oil 9 is introduced which floats on the surface of the liquid and protects the same from contact with gas in the chamber above the oil level. The caustic solution and the oil are introduced through the passage 23.

In the operation of the device, the cap 19 on the nipple 58 of the gauge I3 is removed and the connector 59 inserted in the nipple. The cap is unscrewed to permit air to enter the tube 62. The handle 52 is turned to its upright position as shown in Fig. 2. The plunger 25, if not already in'its lowered position, is lowered to the position shown in said figure and tube 5! is placed in communication with the gas to be tested. The gas passes down through the tube 5I into the upper portion of the chamber I6 and to the atmosphere through the passages 49, 44. After the gas has passed through the chamber for a sufficient length of time to insure that all the air has been forced out of the chamber, the handle 52 is turned to the dotted line position shown in Fig. 3 which will close the upper ends of both the bores 40 and 4|, after which the handle 29 is raised carrying with it the plunger 25 into the upper end of the chamber I 5 partially or entirely above the oil level, as shown in Fig. 3 of the drawings, for exposing the caustic solution to the gas. The carbonic acid gas contained in the chamber will be reacted on by the caustic solution thereby decreasing the pressure which may then, after the plunger has been lowered, be read directly on the scale. The plunger 25 may be raised and lowered, if desired, several times until the reading is constant.

After the plunger 25 is lowered and the reading made, the handle 52 is turned to the position shown in Fig. 2 to permit air to enter the chamber I 6, the connector 69 is removed and after the pressure in the two arms of the gauge has become equalized, the cap I9 is placed on the nipple 58 and the cap 55 screwed down to prevent escape of the liquid in the gauge. The handle 52 is now turned through degrees or one-eighth of a turn downward from the position shown in Fig. 3 for closing all of the passages 49, 4| and 45. The device is then ready for transporting to other places to make additional or further tests.

In Figs. 4 to 6 is shown a modified form of construction. In this form of the device, the receptacle 73 and the gauge M are substantially the same as that already described. The receptacle '73 is provided with a head 55 which may be of any suitable material, that shown being transparent and having a vertical bore 19 in which is slidably mounted a valve I29. The valve I29 comprises a stem TI and a valve head 5I. valve stem I! has a curved recess I8 in communication with an axial bore 86 in the stem. The stem has a channel I9 on another side for conducting gas from the receptacle I3 as will presently appear.

The valve head 8!. having the gasket 89, is secured to the lower end of the valve stem TI and is adapted to close the opening I6 when the valve is at its upper limit of movement. The upper end of the valve stem is reduced to form a nipple 82 to which is adapted to be attached a tube 83 which may be of rubber or the like for conducting the gas to be tested to the receptacle 13. A spring 84 is seated in a recess in the cap I5 and abuts against a nut 65 secured to the upper threadedend of the valve stem I! as shown in Fig. 4 of the The drawings. The spring normally holds the valve M in closed position for preventing the passage of gas into or out of the receptacle-I3. When the valve is in lowered position, as shown in Fig. 4,

gas may enter through the tube 83 and a passage 86 in the stem I? and escape through the curved recess 18 into the interior of the receptacle. The

gas in the receptacle may pass outwardly through the channel or recess I9 to the atmosphere.

A plunger 81, corresponding to the plunger 25 already described, is provided for the receptacle 13. This plunger, in the form of construction shown, fits fairly'snugly in-the upper portion of the receptacle and is provided with a stem 89 extending through the head I5 and terminating in a tube 93 of rubber or the like for conducting the gas to the gauge as will presently appear.

The gauge I4 is of transparent material such, for instance, as Celluloid, or plastic condensation products such as Bakelite, phthalic anhydride, urea condensation product," and the like. It is provided with a U-shaped bore 94 having a long arm 95 and a short arm 95, the short arm 96 being of very much larger diameter than-the arm 95 so that the level of the liquid therein will have a 'much smaller travel than that in the arm 95. F

The upper end of the arm 96 of the bore 94 has a threaded nipple 91 provided with a cap 98. The

cap 98 is provided with an opening 99 through which air may pass when the cap 98 is partially unscrewed. The upper extension of the gauge is provided with an indicator plate IllI with a suitable scale thereon for indicating the height of the liquid level in the longarm 95 and consequently the amount of CO2 gas in the tested sample. The plate IllI may be adjusted along the gauge for properly setting the scale at zero by a thumb nut I92 in the usual manner.

The receptacle 13 is partially filled with a caustic liquid I93 as in the previous construction as previously and on which is a layer of oil I04 described.

In the operation of the device, the valve I20 is lowered by pushing downwardly on the nut-85, which is large enough to constitute a knob or handle, and the gas to be tested is pumped through the tube 83 and passages 86 into themterior of the receptacle I3 and forces the air therein out through the passage I9. This valve is held in lowered position until'the receptacle contains only the gas to be tested, that is, until the air has all been displaced by this gas. The layer of oil I94 will separate this gas from'the caustic liquid I93 and consequently no chemical reaction occurs during the filling of the receptacle with the gas. The valve stem is now. released to permit the valve BI to rise and close the passage It. The cap 99 is released to permit air to enter the short tube 96. The cylinder 81 is now elevated and the caustic solution adhering to the cylinder and to the steel wool contained therein will react on the carbon dioxide contained in the gas thereby reducing the pressure in the receptacle and the air pressure on the mercury column being greater in the short arm 96 will force the level of the mercury in the long arm 95 upward whereby thepercentage decrease in volume of gas sample may he read on the scale through the transparent material of the gauge.

In Figs. 7 to 10 is shown a further modified form of construction. In the use of carbon dioxide indicators, it is sometimes desirable that a small pocket size form of the construction be provided due to its convenience in using and transporting the same. In this form of construction, the entire device, may be, and preferably is, constructed from a single block of material. Any suitable material may be employed, that shown being of transparent material such as Celluloid, or plastic condensation products such as Bakelite, phthalic anhydride, urea condensation product, and the like.

In the form of the construction selected to illustrate one embodiment of this form of the device, the block of transparent material I05 is provided with a bore I 06 which constitutes the receptacle for holding the caustic material. The bore forming this receptacle is drilled from the bottom and extends to a point adjacent to the top of the block. The lower end of the bore is closed by any suitable means as by a rubber plug IE1 and three small bores I33, I09 and I03 extend into the bore I06 from the top of the block.

The bore I06 is adapted to contain a caustic liquid IID on top of which floats a layer of oil III. Within the bore I86 is mounted a plunger II2 comprising the outer cylindrical reticulated portion H3 which contains porous material or material having interstices therein such as steel wool II 4 or the like for increasing the surface of the material as in the previous construction.

The plunger II2, Fig. 8,. has attached thereto a stem H5 which extends upwardly through the bore I08 and has an operating button H6 on its upper end. Suitable packing II'I extends about the valve stem H5 in a counterbore H8 of the bore I08. A screw gland II9 threaded in the counterbore H8 is employed for applying pressure to the packing or gland II! to form an air-tight joint at that point.

Mounted within the bore I09 is a slidable valve stem I2I which is surrounded by a spring I22 seated in a counterbore I23 in the upper end of the block I05 and having a bearing against the nut I24 on the upper end of the stem I2I. The stem IZI has an axial passage I25 extendi g downward t a point adjacent its lower end whereby the passage turns laterally as at I25, shown more clearly in Fig. 8 of the drawings. A

valve I2? is mounted on the lower end of the stem IZI and is adapted to close the opening I09 when the valve is in its upper position. The spring I22 tends to hold the valve in closed position and in such position the passage I25 is closed. The upper end of the valve stem I2I is provided with a nipple I28 to which a tube I29 of rubber or the like, leading to the pump or fan for delivering the gas to be tested to the receptacle, is attached.

The bore IEO has a nipple 85} secured therein and a tube 90 is secured to this nipple. The other end of the tube SI! is connected to a nipple I3I secured in the long arm of the U-shaped tube of the gauge as will presently appear. A suitable clamp I32 may be provided for closing the passage through the tube 93 in a. conventional manner.

, The block I05 is also provided with a U-shaped passage or bore I33. The bore I33 comprises a long arm I34 of small diameter, a large arm I35 of large diameter and a connecting portion I33 which may be of substantially the same diameter as the bore I34. The bores I33 and I35 are adapted to be drilled from the top of the block and the connecting bore I38 from the side thereof. The outer end of the bore I35 may be closed by a plug I31, as shown more clearly in Fig. 7 of the drawings. The upper end of the enlarged bore I35 is provided with a threaded nipple I38 which is adapted to be closed by a threaded cap I39. The cap I39 is provided with an opening MI in one side thereof so that when the cap is partially unscrewed, air may pass through the opening I4I into the bore I35. The upper end of the bore I33 is provided with a nipple I3I for attachment to the tube 90 as previously described.

A scale or angular metal plate I42 having graduations I 33 thereon is adapted to be adjustably secured to the block I05 by means of a set screw I64 in such a position that the graduations can be seen and read through the transparent block I85.

The valve stem I2I is provided with a groove M5 which terminates above the valve I2? but extends longitudinally of the stem to the exterior of the block whereby when the valve is depressed, air or gas within the bore Itfi is free to escape through the passage I09.

In the operation of the device, assuming that the parts are in the position shown in Fig. '7 and that the cap I39 and the clamp I32 are released, the valve stem I2I is depressed and gas entering through I29 is forced into the bore I96 to displace the air therein. The valve stem I2! is then released so that the valve II5 will close the passage I58 and the gauge set at zero afte: which the plunger H2 is elevated by lifting on the stem II 5. The chemical reaction of the caustic liquid on the carbon dioxide of the gas sample will lower the pressure in the bore I06 and this will be indicated by the level of the mercury in the long arm I3 1 of the bore I33. The reading is taken after the plunger is lowered.

It will be noted that in all forms of the device, a plunger is employed for bringing the caustic solution and gas into contacting relation. This plunger may be of any suitable material that is resistant to the action of the caustic solution.

In the form of the construction shown in Figs. 1 and 2, a rotary valve is employed through which the CO2 gas is introduced into the chamber. In the remaining figures are shown two other forms of the device, both of which employ sliding valves for admitting and discharging gas from the gas chamber. The use of a slide valve is preferred over the rotary valve because with the rotary type of valve, the caustic tends to destroy the lubricant and the water in the solution tends to cause rusting of the rotary valve thereby rendering the same difiicult to turn but with the slide from the stem may be made small enough to provide adequate clearance. When the valve is sealed, the stem is protected from contact with the caustic and consequently, the valve is easily operated and does not stick.

While in the form of constructions shown in Figs. 1 to 6, the chamber containing the caustic solution has the lower portion enlarged, this is done merely to increase the capacity of the portion containing the solution. This chamber may be uniform in cross-section throughout its length as shown in Figs. 7 to 9.

It is thought from the foregoing taken in connection with the accompanying drawings, that the construction and operation of my device will be apparent to those skilled in the art and that changes in size, shape and proportion may be made without departing from the spirit and scope of the appended claims.

I claim as my invention:

1, A portable gas testing device comprising a casing having a reservoir, a caustic solution in the lower portion of the reservoir, a porous plunger movable only in a linear path, manual means for depressing said plunger into said solution for saturating the same and for elevating the same into the upper portion of said reservoir above said solution, a pressure gauge element, and means for placing said reservoir in communication with thegas to be tested or with said gauge element.

2. A portable gas testing device comprising a casing provided with a reservoir having its upper portion reduced in cross-section, a caustic solution in the lower portion of said reservoir and having its level in the lower part of said reduced portion, a layer of neutral liquid in said reCeptacle above said level, a porous plunger of slightlyless cross-sectional area than said reduced portion, an air pressure gauge, manual means for lowering said plunger into the lower portion of said reservoir and elevating the same in a linear path into the reduced portion thereof, means for conducting gas to be detected through said reservoir, and means for placing said reservoir into communication with said gauge.

3. In a portable gas tester, a receptacle comprising a chamber partly filled with a caustic solution and having a layer of oil on its upper surface, a roll of fibrous material of fine mesh immersed in said solution beneath the layer of oil, means for introducing a gas into said cham- 'ber, said gas having a constituent capable of reacting on said solution, manual means for elevating said roll in a linear path, a pressure gauge, and means for placing said chamber in communication with said gauge.

4. In a gas tester, a receptacle having a chamher for containing a caustic solution with a layer of oil thereon, a plunger of reticulated causticproof material movably mounted in said chamber, manual means for moving said plunger in a linear path out of contact Withsaid solution, said receptacle having a cap provided with a plurality of passages for conducting air and CO2 gas to and from said chamber, a valve having passages therein, a pressure gauge, and means including 5a handle for turning said valve for placing said chamber in communication with the passage for conducting gas to be tested to said chamber, in communication with the atmosphere or in communication with said gauge alone.

5. In a gas tester, areceptac'le having a chamiber therein, a cap for closing the upper end of said chamber, said cap having two vertical passages therethrough for conducting gas into and out of said chamber, a valve intercepting said openings, a lateral passage extending laterally 'from said valve to the side of said cap, a pressure gauge, a conduit in communication with said lateral passage and said gauge, a conduit connected to one of said vertical passages for conducting gas to be tested to said chamber, said valve having two bores therethrough adapted to ,register with said vertical passages and having a lateral passage from one of said bores adapted to register with said lateral passage, means for turning said valve to one position for conducting gas into and out of said chamber and to a second position to close said vertical passages and opening said lateral passage to place said chamber in communication with said gauge, said means being adapted to turn said valve to a third position to close all of said passages, a vertically movable plunger of wire cloth within said chamber, and manually operated means for raising and lowering said plunger in a linear path.

6. In a gas testing apparatus, a receptacle having a chamber, said chamber being enlarged at its lower end and restricted at its upper end and containing a caustic solution, the level of which is adjacent to, but above, the level of said enlarged portion, a layer of oil on said solution, a plunger of wire cloth immersed in said solution, manually operated means for raising said plunger vertically in a linear path above the level of said solution and for lowering said plunger below the level of said solution, means for conducting gas to be tested through passages into and out of said chamber while said plunger is immersed in said solution, means for closing said passages, and

means for measuring the reduction in pressure within said chamber due to the reaction of said gas on said solution.

7. In a gas testing apparatus, a receptacle, a caustic solution in one portion of said receptacle, a plunger comprisinga porous mass of. material, means for reciprocating said mass vertically in a linear path into and out of contact with said caustic solution in said chamber, a gauge in communication with the upper portion of said chamber for indicating gas pressure therein, and a valve for introducing gas to be tested into said chamber;

8. In a gas testing apparatus, a receptacle,.a caustic solution in said receptacle, a layer of neutral liquid on said solution, a pressure gauge, means for placing said gauge in communication with said receptacle, a valve for admitting and permitting discharge of gas from said receptacle, a plunger comprising a porous mass in said receptacle, and manually operated means for reciprocating said mass in a linear path below the level of said liquid and to a position for exposing said mass to gas contained in said receptacle.

9. In a gas testing apparatus, a receptacle, a caustic solution in one portion of said receptacle, a layer of neutral liquid in said solution, a plunger comprising a porous mass of material, manually operated means for reciprocating said mass in a linear path into and out of contact with said caustic solution in said chamber, a gauge in communication with the upper portion of said chamber for indicating gas pressure therein, a valve for introducing gas to be tested into said chamber, said gauge comprising a U-shaped passage in communication with the air at one end and with said receptacle at the other, a liquid in said passage, a graduated indicator plate, and means for adjustably mounting said plate on said gauge, said plate being so graduated and adjusted on said gauge as to indicate the percentage of CO2 gas in a given sample.

10. In a gas testing apparatus, a chamber for holding a caustic solution, means for introducing gas to be tested into said chamber, said means comprising a slidable valve stem movable in a linear path and having passages leading into and out of said chamber, means for intermingling said gas and solution, a valve carried by said stem for preventing discharge of gas from said chamber when said valve is closed, and

means for measuring the amount of gas absorbed by said solution.

11. In a gas testing apparatus, a receptacle for containing a caustic solution, said receptacle having a passage, a valve having a stem slidably mounted in said passage and a head for closing said passage, said stem having an axial bore for admitting gas to said receptacle for testing the percentage of CO2 gas therein, said bore terminating at the periphery of said stem outwardly of said head, said stem also having a passage extending to the exterior of said receptacle and terminating outwardly of, but adjacent to, said head, whereby when said valve is at its inner position, gas may enter said bore and gas in said receptacle escape through said secondnamed passage, spring means for normally closing said valve, means for mixing said CO2 gas and caustic solution, and means for indicating the amount of CO2 absorbed by said solution.

12. A gas testing apparatus comprising a solid block of transparent material having a body portion and an offset, said body portion having a bore extending upwardly from its lower side for forming a liquid containing receptacle, said body portion and offset having a U-shaped passage therein forming a pressure gauge having a long arm, a short arm and a connecting portion, said short arm being of greater diameter than the long arm, said passage being filled with a heavy liquid, said long arm being in communication with said bore, a graduated scale adjustably mounted on said block rearwardly of said long arm with the graduations visible through the block, a caustic solution with a top layer of neutral liquid within said receptacle, a plunger having interstices therein movable to a position beneath the surface of said neutral liquid and to a position at least partially above said liquid, manually operated means for raising and lowering said plunger in a linear path, a slidable valve for admitting gas to be tested to said receptacle, said valve comprising a head and a stem, said stem having a bore and a passage extending to the exterior of said receptacle and terminating on the periphery of said stem adjacent to said head, and a spring for normally holding said valve head in closed position.

13. A small portable gas testing apparatus comprising a block of transparent material having a caustic solution container therein, a pressure gauge therein, means for placing said gauge and receptacle in communication, means including a single sliding valve for admitting gas into and permitting its discharge from said receptacle, means for intermixing said gas and solution and a graduated scale for indicating the percentage of carbon dioxide gas in a given sample of gas introduced through said valve.

14. In a gas testing apparatus, a solid block of transparent material having a vertical bore therein opening at the bottom and forming a receptacle for containing a caustic solution, a caustic solution in said receptacle, a layer of neutral liquid on said solution, a closure for said receptacle, a U-shaped bore in said block and having a long and a short arm opening upwardly, a liquid in said arms, a passage leading from said receptacle to the exterior of said block, a single slidable valve in said passage for the admission of gas to said receptacle and the discharge therefrom, means for causing intermingling of said gas and. said caustic solution, means for placing said long arm in communication with said receptacle, and a graduated scale on said block adapted to be adjusted thereon to bring a predetermined marking at the level of the liquid in said gauge when the liquid is of the same level in both arms.

15. In a gas testing apparatus, a chamber for holding a caustic solution, means for introducing gas to be tested into said chamber, said means comprising a slidable valve stem movable in a linear path and having passages leading into and out of said chamber, said passages being opened when said valve is moved to its innermost position and closed when said valve is moved to its outermost position for trapping a predetermined sample of gas to be tested, means for causing said gas and solution to contact each other, and means for indicating the relative amount of gas absorbed by said solution.

16. In a gas testing apparatus, a chamber for containing a caustic solution, means for introducing gas to be tested into said chamber, said means comprising a valve stem having a rectilinear movement and provided with inlet and outlet passages for introducing and discharging gas from said chamber, means for separating said gas from said solution while said gas is being introduced into said chamber, means for effecting contact between said gas and solution, and means for indicating the relative amount of gas absorbed.

17. In a gas testing apparatus, a chamber for containing a caustic solution, means including a slidable valve stem movable in a linear path and having inlet and outlet passages for conducting gas to said chamber when said valve stem is depressed, means for elevating said stem for promptly closing said passages when said stem is released for trapping a predetermined quantity of gas in said chamber, means for separating said gas from said solution while said gas is being introduced into said chamber, means for effecting contact between said gas and solution, and means for indicating the relative amount of gas absorbed.

FRANK W. DWYER. 

